HP-UX System Administrator's Guide: Routine Management Tasks

NOTE: Put your most frequently accessed information on your fastest disks, and
distribute the workload evenly among identical, mounted disks so as to prevent
overload on a disk while another is under-utilized. This can often be accomplished
by moving swap areas and heavily accessed file systems off the root disk, or by
using disk striping, LVM, and/or disk mirroring to spread I/Os over multiple disks.
See also “Checking Disk Load with sar and iostat” (page 194).
Network Bottlenecks:
• Excessive demand on an NFS server.
• LAN bandwidth limitations
Guidelines
Performance is a notoriously difficult topic on which to provide definite advice; these
guidelines should not be taken as formal recommendations from HP, but merely as
the closest the authors could come to distilling a consensus from the observations of
the experts they consulted.
• Keep NFS servers and their clients on the same LAN segment or subnet. If this is
not practical, and you have control over the network hardware, use switches,
rather than hubs, bridges and routers, to connect the workgroup.
• As far as possible, dedicate a given server to one type of task.
For example, in our sample network (see HP-UX System Administrator’s Guide:
Overview) flserver acts as a file server, sharing directories to the systems, whereas
appserver is running applications.
If the workgroup needed a web server, it would be wise to configure it on a third,
high-powered system that was not doing other heavy work.
• On file servers, use your fastest disks for the shared file systems, and for swap.
— Distribute the workload evenly across these disks.
For example, if two teams are doing I/O intensive work, put their files on
different disks or volume groups. See “Checking Disk Load with sar and iostat”
(page 194).
— Distribute the disks evenly among the system’s I/O controllers.
• For shared HFS file systems, make sure the NFS read and write buffer size on the
client match the block size on the server.
You can set these values when you import the file system onto the NFS client; see
the New NFS File System menu on HP SMH. See “Checking NFS Server/Client
Block Size” (page 194) for directions for checking and changing the values.
192 Managing System Performance